So the EC is chambered in 223. Meaning you can't use 5.56, correct? But now there's a 14.5 version with pinned flash hider. Do you guys really think a 14.5 barrel is going to be chambered in 223? Surely it's a Military unit. Cool rifle I'm just not sure I want an AR limited to 223 only.

Colt barrels are all 5.56 compatible.  The .223 stamping  is for mil. Cart. Restricted nations and sales.

https://www.ar15.com/forums/Industry/Rare-Colt-European-Specification-Carbines-Available/29-303833/?page=1

WWGJD? Well, Gun Jesus says no problemo shooting 5.56 out of .223 rifle.  


https://youtu.be/-fmcdaAOkY4

Ok thanks for link to other thread I did not see that

Based on the tracking # hope to have mine tomorrow (Monday) evening.

First thing to check is the chamber with chamber gauge. My "guess" is .223.

Don't shoot 5.56 out of the .223 barrels. These are confirmed .223 chambers so shooting 5.56, while may work to some degree, is putting extreme pressures in the chamber area. Each time you fire it, it's basically putting near proof load pressures in there. It's then not a question of if, but when it'll cause problems.

Knowing Colt, if they sold these in Europe, you can bet they are actual .223 spec and not just stamped .223 but chambered in 5.56 like the American ones. Many European countries have strange laws that let them shoot non-military rounds and .223 is considered non-military.

At about 4:50 into that video he barely mentions the very few exceptions and then spends the rest of the video (pretty much ALL of the video) telling everyone not to worry about it. At one point he even points to HIS personal .223 ('military looking' .223 rifle BTW - which should be a subtle hint as to its real / actual chamber measurements...) and starts going on and on about how many rounds of 5.56 he has shot through it with no issues whatsoever.


If he had ever actually owned and 'tested' a barrel with a real deal, nice and tight .223 match chamber - That same 5.56 ammo fired in that particular chamber might have not have worked out so well and he 'might' have gone into a little bit more detail (and for a lot longer) than he did.












The last time I ran out of my .223 ammo and decided to keep on shooting my .223 barrel with the 5.56 ammo I had around in the other can the results were less than 'optimal'.



Not suggesting anything exploded or that anything blew up because none of that happened.

The particular 5.56 rounds I had in my other can that day were some sort of NATO spec SS109 garbage. (It's ALL garbage, minute of milkjug, craptastic ammo that nobody with a brain would ever shoot out of an otherwise 'good' barrel IMHO)



Popped primers galore, split necks, broken necks (lovely when your firearm wants to 'try' and chamber another round but a case neck is left behind in the chamber and in the way of that happening), etc.


I had NO brass left over from that 'experiment' that was ever going to be reloadable.



As much as I like that guy he is sadly lacking experience here in this particular area.


I would bet money that any Colt 'anything' produced and labeled as to having a .223 chamber is not anywhere near as tight of a chamber as what I am discussing and calling a 'real' .223 chamber. (honked the f out .223 is not the same as .223)

Will wait and and watch as those things get out there and actually used by more people and hope that someone does some actual measuring or some real testing.

None of that has happened as of yet.    

Add to the equation that 5.56 ammo is not allowed to civilians but surplus 556 ammo is sold regularly by milling the 556 stamping off the case and labeling the box as 223

My FFL just called, mine is here, super excited to go get it and measure the chamber.

Its here, its basically identical to the  European Colt 16" model from last year except for the 14.5" P/W and the Quad Rail. Rail is held in place with 4 Torx screws.

Chamber is definitely .223 using the M Guns gage you can see in the picture and the headspace is tight at 1.4636.

My only gripe was the inside of the Colt box was badly damaged from the gun during shipment and no plastic bag. As I was bitching about the plastic bag missing the guy at the counter said, oh we have that we threw it in the trash. So dumpster diving I went and I got that bag in good order. I fixed the box with some super brown tape for the most part.

The gun is perfect so I am happy!

Funny thing the gun guys at the counter felt the need to tell me the barrel was marked .223 and be careful of my ammo choice lol.

Like last years gun, 10rd PMAG, a lock and a Spanish manual.

the QR code scanned 21032024   so March 21, 2024 build date.

That rail is kind of cool. Being 5.56 is a NATO round, I would think the European models would be 5.56. Kind of neat though in a way

Well I’m glad I grabbed a spare 5.56 Socom barrel from Brownells last year

Looks nice~~

I'm really liking this quad rail. 4 torx screws lock it down tight.

Lay a steel rule along the top rail when torqued.

Many of them will flex and form a dip in the middle like a canoe.

I took a 12" straight edge off a framing square and laid it over the rail and lower receiver, your correct Tig, I should have seen it with my eyes only, it does have a pronounced dip in the middle.

Annoying/inherent trait common with drop in quads that secure 2 halves in that manner.

So, they got my money.  It's been a long while since I've bought a gun, have a Colt upper, but never owned a full Colt AR and this does look interesting.   The .223 chambering is not ideal, particularly given the quantity of XM193 I already own.  But it's not that big a deal to add 500-1000 rounds of .223 to the stockpile.  Will probably put a red dot on it, but I have an extra one already.  Wondering if I want to upgrade the trigger can I use a standard Geissele or LaRue.  Seem to remember reading somewhere that Colt has enlarged/non-standard holes for triggers.

Not the case on modern lowers.

1990-~2009 for large pin Colt lowers.

Great, I actually think I've got an extra "blemished" Geissele trigger I bought a while ago because it was cheap and you never know when you're going to need another trigger.  Guess this just shows how old I am/how long I've been buying AR's as I remember this used to be a thing.

I know some people are thinking about just putting these away because they are somewhat rare and may eventually become a collectable.  Can't see myself doing that since this all my guns are shooters and at $900 this just seems like a bargain Colt.  I mean what's the point of keeping this untouched in my safe for 10 years so I can maybe sell it for $1,000 or $1,100?  If I was interested in Return on Investment I'd just put the money in a T-Bill/money market account.

US military SCATP
The United States Armed Forces defines test procedures for 5.56mm NATO in SCATP-5.56, 7.62mm NATO in SCATP-7.62, and .45 ACP in SCATP-45.[11] These procedures are based on the SAAMI test methodology.

5.56 Maximum pressure (SCATP 5.56) 55,114 psi
223 Maximum pressure (SAAMI) 55,000 psi

As I said above I ordered mine on Thursday after debating for a day or two.  Really don't need another AR, but I've also never owned a complete Colt and this one is both unusual and reasonably priced.  Glad I didn't wait any longer as it looks like they're now OOS.  Maybe I'll do a quick write up after mine arrives.

Yep, they only had about 100 to start with.

Good on you for getting 1, you will not be disappointed.

Without a chamber casting and some real measurements that does not tell you much other than it is tight 'somewhere'.

You no idea where or what the angles are or if 5.56 is really going to be a problem.


Buy some cerrosafe and find out for sure...  

Mine doesn't pass 5.56 head spacing.  Bolt closes very tight on 1.4636, does NOT close on 1.4646. Therefore I see no reason at least for me to use 5.56 in mine. Anyone else feel free to do what you want.

As for the cerrosafe, if you have some can you do it? I would be interested in the results. I have now put the gun away in my safe. Moving on to my next gun in the que.

I just measured the overall chamber length of 3 different AR barrels to compare with my 16" and 14.5" 6920-EC barrels.  

I wanted to get some idea of the difference in the .223 REM barrel bullet jump as compared to the 5.56 jump.

I used the Hornaday OAL gauge with a  Hornaday 55gr BTFMJ bullet.

Results:

14.5" Colt CR6920-EC: 2.350 .223 REM
16"    Colt CR6920-EC: 2.350 .223 REM
16"    Colt CR6920:      2.355 5.56 NATO
16"    Colt LBD6721:    2.355 5.56 NATO
16"    PSA:                  2.355 5.56 NATO
16"    FN:                    2.370 5.56 NATO
16"    DD:                   2.370 5.56 NATO


Very little difference between the .223 and 5.56 Colt barrels, .005 is not much.

I can't tell you what this means as far as shooting 5.56 in the .223 EC rifles.

I do know that some of my reloaded 5.56 rounds are hot and I show no over pressure signs after shooting in the EC rifles.

Basically, the freebore/leade/jump depends on the barrel manufacturer.

Good information!  Thanks for posting that.

A SAAMI spec 223 Remington chamber will have a significantly shorter jump to the lands than a Colt 5.56 NATO chamber. Here’s what Hornady’s website says about the difference between 223 Remington and 5.56 NATO chambers:

“The second and most important difference between the two is the fact that a 5.56 NATO chamber has a .125” longer throat.”

Obviously, there will be some minor variations in these types of measurements depending upon the headspace of the brass case used when obtaining the measurement, the headspace of the chamber of the particular barrel being assessed, the particular manufacturer of the 223 Remington reamer used to chamber the barrel, the thickness of any lining of the chamber/bore, the particular lot of the Hornady 55 grain FMJ bullet used and the number of rounds fired from the barrel at the time of the measurements, etc.

I pulled a few low-round-count Colt 5.56 NATO chambered barrels out of the safe and measured the COAL for the Hornady 55 grain FMJ bullet seated to lands in them  The average COAL was 2.356”.

Next, I measured the COAL for the Hornady bullet seated to the lands in one of my 223 Remington chambered AR-15 barrels.  It was 2.252”, for a difference of 0.104”.  That’s more than twenty times the difference that you found between your Colt 5.56 NATO chambered barrel and the supposedly 223 Remington chambered Colt barrel and the minimum chamber headspace specification for the 223 Remington and the 5.56 NATO are the same; 1.4636”.  The 1.4646” figure that people like to throw around is a Colt in-house, US mil-spec that Colt uses for US mil-spec rifles and carbines.  If your readings are correct then these carbines that Colt is claiming to have a 223 Remington chamber don't meet the SAAMI 223 Remington specs.

Without even examining the actual numbers, all one has to do is visually look at  chambers to see that there is a significant difference in the jump to the lands between a SAAMI 223 Remington chamber and a 5.56 NATO chamber.



Raw pic courtesy of Ned Christiansen


….

Many thanks to everyone whose posted actual measurements/info.  As the, hopefully, future owner of one of these rifles (AU still hasn't shipped it) this info. is very helpful - at least if I am interpreting the data properly.  So, it sounds like the EU Colt's don't really have a true .223 chamber and that they are actually pretty damn close to what would be considered a traditional 5.56 chamber.  Am I interpreting this data correctly?  And, if so, does this mean that there really shouldn't be much of an issue shooting something like XM193 (which I have a ton of) through this rifle?

That's my take away and keep an eye on any over pressure signs.

I doubt we'll get Molon to commit.  I don't think I would if I had his body of work. To much at stake.

Quantity of 14.5" p/w CR6920-EC will be in the 400 range. AU will ship. It took them about 5 or 6 days to ship mine. They are a small operation and are pretty busy most of the time.
Shooting XM193 will have to be your choice.

Just a trusted acquaintance. They weren't all put on the market at one time. You will see more.

Thanks for the info.

These are nice rifles, I want another.

Agree, very nice, one of the top 5 in my Colt collection easily. I too am going to order another one. And that price,